HIGH PERFORMANCE HYDROXYL EXCHANGE MEMBRANE (HEM) FOR ALKALINE FUEL CELL APPLICATIONS

The Millitary has a strong need for very high-energy density (>1000 WH/kg), light weight power sources for communications and other advanced electronic devices The possible solution is replacing the battery with proton exchange membrane (PEM) based hydrogen fuel cell. However, hydrogen storage and handling is a problem. Direct oxidation fuel cell (DOFC) with a PEM is a quite attractive alternative. However, due to slow reduction and oxidation kinetics in the acidic media and fuel crossover issue, those systems have not reached their full potentials. It is well known that electrochemical oxidation of fuel and electrochemical reductions of oxygen are kinetically more favorable in an alkaline media at low temperature (T<100oC). Furthermore, alkaline electrolyte offers the best prospects for using non-noble metal as the catalyst. Recent reports showed promising results for alkaline fuel cell based on hydroxyl exchange membrane (HEM). However, due to limited availability and low performance of such membranes, a lot of development work is still urgently needed in order to pave the way for developing high energy density AFCs. Driven by the strong market pull, we invented a novel HEM, which promised to have the following advantages, 1) high ionic conductivity; 2) excellent thermal stability; 3) much better chemical and electrochemical stability; 4) low cost and 5) excellent manufacturability. Therefore, this innovative HEM can meet the stringent requirements as the membrane material for both AFC and direct ethanol AFC applications.